A wireless network, such as a cellular network, can include an access node serving a number of end-user wireless devices or user equipment (UE) (hereinafter “wireless devices”) in a geographical area covered by the radio frequency transmission of the access node. When the access node transmits data to the end-user wireless devices via an antenna, the signal may be attenuated due to various reasons, such as long distance, severe weather conditions (e.g., rain, snow, heavy cloud, etc.), buildings, trees, or other obstacles in the path of signal transmission. As a result of the signal attenuation, certain data may be lost or otherwise damaged or altered, resulting in poor signal transmission quality. To compensate for the signal attenuation and therefore to improve transmission quality, the access node may implement a transmission diversity scheme, in which two or more transmitting ports of the antenna may be used to transmit the same data or signal. Reliability and quality of signal transmission may be significantly improved using the transmission diversity scheme. The level of transmission diversity may be related to the number of transmitting ports. When more transmitting ports are used, higher levels of transmission diversity may be achieved.
In currently implemented 4G wireless networks, only one two-transmitting-port diversity mode is used, which leads to up to 3 dB gain in signal quality or in the level of signal received at the end-user wireless devices. The two-transmitting-port diversity mode is typically used to enhance performance at cell edge, i.e., at the boundary of a coverage area of the access node. In such a transmission diversity mode, the same data is transmitted by the access node from two antenna elements or ports using different encoding.
In certain circumstances, the signal attenuation may change over time as the environment changes. For example, when the weather changes (e.g., rain, snow, etc.), the signal attenuation may change. When the landscape changes (e.g., number of buildings), the signal attenuation may also change. In some circumstances, the signal attenuation may change as end-user wireless devices move from one place to another. When the wireless devices move from a portion of the coverage area supporting 4G wireless communications (using lower frequencies) to a portion of the coverage area supporting 5G wireless communications (using higher frequencies), the signal attenuation may change. When the signal attenuation changes, levels of signals received at the end-user wireless devices may change. For example, the levels of signals may experience a reduction of greater than 3 dB (e.g., 5 dB, 10 dB, etc.). Moreover, in wireless networks that use high frequency spectrum, such as frequencies higher than 8 GHz, e.g., 28 GHz, 39 GHz (e.g., those of 5G wireless frequencies ranging from about 30 GHz to about 300 GHz), the signals are more susceptible to signal attenuation than wireless networks that operate on low frequency spectrum (e.g., 900 MHz, 2.5 GHz, etc.). Furthermore, with 5G wireless technologies, full dimension multi-input-multi-output (FD MIMO) may be used in antennas. An antenna that supports FD MIMO may use an array of a large number of antenna elements or ports, such as 16×16, 64×64, etc. Therefore, as higher frequencies are used for wireless communication and as a large number of antenna elements are available for transmitting signals, there is a need for systems and methods that are capable of dynamically selecting the number of transmitting ports of an antenna for an access node.